Stereoscopic image detection devices are known in the art. When such devices are used for Minimum Invasive Surgery (MIS) applications, it is desirable to obtain a combination of minimal shaft cross-section and high image quality.
Stereoscopic endoscopes are typically characterized, at least partially, by separate optical channels. Each such channel provides separate ray tracing from the object toward human eyes or photoelectric sensors. Another type of conventional stereoscopic endoscopes uses a common optical system, while the optical channels are separated using time division, or according to light polarization direction.
Production tolerances and separate adjustment of each optical channel in a conventional stereoscopic endoscope may cause different optical characteristics of each optical channel, namely different magnification, focusing, off-set and tilt. This makes the requirement of high image quality more difficult to achieve.
U.S. Pat. No. 5,471,237 issued to Shipp, and entitled “Single Lens Stereoscopic Video Camera”, is directed to a stereoscopic video camera system, which uses a single objective lens system mounted at the distal end of a surgical endoscope. According to one embodiment, the camera is used to provide images of an object located near the distal end of an endoscope, from two different eye perspectives. The endoscope includes a single objective lens system and an electronic shutter. The electronic shutter includes left and right optical zones, each capable of assuming an opaque state and a transmissive state. A drive signal causes one zone to become opaque while the other is transmissive, and vice versa.
U.S. Pat. No. 5,527,263 issued to Zobel et al., and entitled “Stereo Endoscope”, is directed to a stereo endoscope. The shaft of the stereo endoscope includes two optical systems, arranged in close proximity to each other, and a housing, located on the proximal end of the shaft. A stereo optical device connects at the proximal end of the optical systems, thereby providing a stereo view into the optical system.
U.S. Pat. No. 5,689,365 issued to Takahashi et al., and entitled “Stereoscopic-Vision Endoscope”, is directed to a stereoscopic endoscope. The endoscope includes a main optical system having a single optical axis, and a rotary optical system having right and left optical axes. An object is illuminated, thereby providing a left image and a right image to the main optical system, with a parallax difference there between.
U.S. Pat. No. 5,743,846 issued to Takahashi et al., and entitled “Stereoscopic Endoscope Objective Lens System Having a Plurality of Front Lens Groups and One Common Rear Lens Group”, is directed to a stereoscopic endoscope. Two images, having a parallax from each other, are formed by two respective objective optical systems, in spatially separated positions. The images are transmitted by a relay optical system, and separately formed on a photoelectrically converting surface of an image taking device.
U.S. Pat. No. 6,154,315 issued to Street, and entitled “Apparatus and Method for Stereoscopic Endoscopy”, is directed to a stereoscopic endoscope. The endoscope comprises a birefringent slab of calcite, an objective lens assembly, a relay system, a lens, a reflecting prism, a polarizing beam splitter, a lens and two CCD arrays.
Light from two points in an object field travels through the birefringent slab, before reaching a entrance pupil of the optical system. The birefringent slab affects the light, when viewed from the object field, in a manner equivalent the endoscope presenting two displaced entrance pupils. The polarizing beam splitter transmits light having one polarization direction, to one of the CCD arrays, and reflects light having an orthogonal polarization direction, to the second CCD array.